Polymers containing benzazole units (i.e., benzimidazole, benzoxazole, or benzothiazole) in the polymer backbone are well-known in the art. The outstanding thermal and chemical stabilities of this class of polymers have suggested broad utility in high-temperature films, laminates, adhesives, fibers, and insulating foams. In general, these polymers are prepared by the reaction of ortho-substituted aromatic amines with dicarboxylic acids or their derivatives at high temperatures. These polymers have been reviewed by P. E. Cassidy, "Thermally Stable Polymers", Marcel Dekker, Inc., New York, N.Y., 1980, Chapter 6, pp. 141-221.
French Pat. No. 887,530 (1943) describes the preparation of high molecular weight polyamides and polyesteramides by reaction of bisazlactones with aliphatic diamines, diols, or aminoalcohols. Polyamides from bisazlactones and diamines have also been described by C. S. Cleaver and B. C. Pratt, J. Am. Chem. Soc., 1955, 77, 1541-1543, and by Ueda, et al. J. Polym. Sci., Polym. Chem., 1978, 16, 155-162. Ueda, et al., J. Polym. Sci., Polym. Chem., 1975, 13, 659-677, disclose the preparation of polyamides from 4,4-arylidenebisazlactones. Although some of these references disclose polyamides prepared from aromatic diamines, none teach the reaction of bisazlactones with bis(ortho-substituted aromatic amines).
The reaction of 4-arylideneazlactones with ortho-substituted anilines was described during the course of our investigations. Habib, et al., J. Prakt. Chem., 1983, 325, 685-688, report the isolation of a variety of compounds including benzimidazoles, depending upon reaction conditions, from the reaction of these 4-unsaturated azlactones with o-phenylenediamine. More recently, Harb, et al., Heterocycles, 1986, 24, 1873-1881, report the preparation of benzimidazoles or benzothiazoles by reaction with o-phenylenediamine or 2-mercaptoaniline respectively.
To applicant's knowledge, no polymers have been prepared previously incorporating the 2-amidomethylbenzazole unit.